1. Field
Aspects of embodiments according to the present invention relate to a touch screen system.
2. Description of Related Art
A touch screen panel is an input device that selects instructions displayed on a screen, such as an image display device, etc., by using a person's hand or an object to input instructions of a user.
To this end, the touch screen panel is provided on a front face of the image display device and converts positions that are directly touched by a person's hand or an object into electrical signals. Therefore, the instructions selected at the touched positions are received as the input signals. As the touch screen panel can replace a separate input device, such as a keyboard or a mouse, that is operated by being connected to the image display device, the application field of the touch screen panel is being gradually expanded.
Types of the touch screen panel include a resistive type, a light sensing type, a capacitive type, etc.
Recently, there has been increased interest in a multi-touch screen system capable of performing multi-touch recognition through the touch screen panel. In particular, in the case of the capacitive type, the multi-touch recognition may be implemented as a self capacitance type or a mutual capacitance type. When at least one finger of a person touches the surface of the touch screen panel, the capacitive type touch screen panel detects a change in capacitance formed in sensing cells that are positioned at the touched surface to recognize the touched positions.
However, according to these schemes, it is difficult to recognize more precise touch positions through the touch by a person's finger.
In order to overcome the above-mentioned problems, a sharp stylus may be used. In the case of a passive stylus, the change in capacitance is very slight at the touched surface, such that it is difficult to detect the touched position. On the other hand, an active stylus can generate an electric field. The generated electric field has an effect on the sensing cells of the touch screen panel corresponding to the actually touched position and other sensing cells coupled to a sensing line that is affected by the generated electric field, such that it may be impossible or difficult to determine the touched positions.